Conventional power detectors are used to monitor input power or output power of a signal. Generally, power detectors are designed to not affect a system when placed in a transmission path. Process, voltage and/or temperature (PVT) variations and/or system noise may result in a mismatch between amplifier inputs. At low power operation, the mismatch may limit an operating range of the power detector. Without accurate measurement and control of gain and reflected power in a wireless transmitter, transmission quality may be poor and/or multi-path issues may result.
Conventional power detectors can implement a linear-in-mag power detector and perform log correction in a digital domain. However, the digital circuitry may be large and/or unsuitable for radio frequency (RF) chips. In mm-wave implementations, linear-in-dB power detectors that are based on saturation are unsuitable due to high power consumption and large area requirements.
It would be desirable to implement a linear-in-dB log-amp with calibration for power detection.